Drilling jig

ABSTRACT

A DRILLING JIG IN WHICH SEVERAL DRILL BUSH HOLDERS ARE ADJUSTABLY MOUNTED OVER A BASEPLATE. EACH HOLDER IS APPROXIMATELY U-SHAPED AND NORMALLY FASTENED TO THE BASEPLATE BY ITS BIGHT PORTION. A SCREW CONNECTING THE TWO LEG PORTIONS OF THE HOLDER PERMITS THE FREE ENDS OF THE LEG PORTIONS TO BE MOVED TOWARD AND AWAY FROM EACH OTHER FOR CLAMPING A SPLIT RING HELD BETWEEN THE FREE ENDS ABOUT A DRILL BUSH. THE HOLDERS THE POSITIONED ON THE BASEPLATE BY MEANS OF A GAGE HAVING TWO ARMS ELONGATED AT RIGHT ANGLES TO EACH OTHER AND CARRYING RESPECTIVE SLIDES. COOPERATING ABUTMENTS ON ONE SLIDE AND ON THE BASEPLATE DETERMINE THE PORTION OF THE GAGE WHICH IS GUIDED RELATIVE TO THE BASEPLATE, AND A CONICAL ELEMENT ON THE OTHER SLIDE MAY BE ENGAGED COAXIALLY WITH A DRILL BUSH IN THE HOLDER TO BE POSITIONED.

United States Patent Inventor Viktor Clio Zurich, Switzerland Appl. No.770,711 Filed Oct. 25. I968 Patented June 28, i971 DRILLING .IIG 5Claims, 7 Drawing Figs.

US. Cl. 408/115, 24/ 1 9.241257 ht. B23b 47/28, 1323b 49/04 FieldofSeareh 24/19, 257; 77/62 Relerences Cited UNITED STATES PATENTS820,965 5/1906 Froggatt 77/62 1,235,031 7/l9l7 Holmgren 77/62 25 o O F2| 3 l0 4 i n= a; seeeee- Primary Examiner-Francis S. Husar ABSTRACT: Adrilling jig in which several drill bush holders are adjustably mountedover a baseplate. Each holder is approximately U-shaped and normallyfastened to the baseplate by its bight portion. A screw connecting thetwo leg portions of the holder permits the free ends of the leg portionsto be moved toward and away from each other for clamping a split ringheld between the free ends about a drill bush. The holders thepositioned on the baseplate by means of a gage having two arms elongatedat right angles to each other and carrying respective slides.Cooperating abutments on one slide and on the baseplate determine theposition of the gage which is guided relative to the baseplate, and aconical element on the other slide may be engaged coaxially with a drillbush in the holder to be positioned.

PATENTED JUN28 I971 SHEET 1 BF 2 I :NTUR. 1/ K To BY mm M W4 d w CHOAGE/W's PATENTED JUN28 19m SHEET 2 [IF 2 OOOOQOQO INVEN'I'UR. K R CHBYz/QM [Mag [bum/LL AGE/v75 DRILLING JIG The present invention concernsa device designed to solve in a general manner the most varied problemsarising in connection with a drilling and boring device, to an extentwhich is not feasible with the known systems. The chief object here isthe quick provision of a ready-for-use tool for small productionbatches. The main feature of the new device is that, for universality ofapplication, it consists of a combination of the following new elements,in particular that it comprises interchangeable clamping rings whichserve to clamp the drill bushes of various sizes and which coact withthe bush holders and the holder supports and which can be set to therequired position by means of a coordinate sliding gauge, while aspindleless coarse and fine fixing system serves to fix the work, thearrangement being such that the said two fixing elements are mounted asa whole on a switchable ball bearing with a view to facilitating thecentering of the drills, and that in addition an adjustable angle scaledial is provided for the setting and measuring of interrelated boreholeson round workpieces.

With the said invention, the following new results have been achieved intoolmaking:

l. The known adjustable bush holders only permit bushes of a particularsize and of the same outside diameter to be fixed, so that a wholenumber of different bush holders is required to accommodate bushes ofvarious sizes. The new universal device differs from these known systemsin that it has a universal horseshoe-shaped bush holder which can takeall the usual sizes of bushes by means of interchangeable clampingrings.

2. With the known bush holders, the bush is fixed in a bore inside therelatively large holder head, so that two bush holders can only be movedso near to each other as the width of the holder head permits, so thatfor closely spaced bores they cannot be used at all. This drawback hasnow been eliminated by the new thin-walled clamping ring coacting withthe new bush holder, because now the bushes are located at the open endof the horseshoeshaped holders and thus stand clear except for the widthof the holder shank tip. This permits the bushes to be moved togethervery closely, i.e. almost until they touch, owing to the thinness of theclamping ring wall.

. The new device has yet another advantage in that, for the fixing ofthe work, it is mounted over a new spindleless fine-fixing system withself-acting parallelism without lateral guide. As is known, in a fixingtool, such as a vice, the parallelism of the two fixing jaws is ofparamount importance. To ensure this, the fixing jaws must have a sideguide of maximum length and strength, and this also in volves expensivemachining to close tolerances. A long guide of that type takes up agreat deal of room and thus reduces the fixing width of the fixing tool.In the new device, moreover, the tiltable jaw also has a down-pullingeffect.

A special coordinate sliding gauge permits the bushes to be set veryquickly to the exact positions required.

. For easier centering, the'whole unit can be engaged with a switchableball bearing and disengaged again.

6. The adjustable angle scale dial was devised for the quick setting andmeasuring of interrelated boreholes on round workpieces.

An embodiment of the said invention is illustrated by way of example inthe attached drawings, wherein:

FIG. 1 is a top-view of the whole device; FIG. 2 is a longitudinalsection through the device along line A-B;

FIG. 3 is a top-view of the coordinate sliding gauge;

FIG. 4 is a crosssection through the said gauge along line C-D;

FIG. 5 is a diagram of the angle setting unit for round workpieces;

FIG. 6 shows the pointer fastening means;

FIG. 7 shows the switching unit of the ball bearing.

BASIC UNIT The basic unit is shown in FIGS. 1 and 2. The base of thedevice comprises a baseplate l, a fixed jaw 2, a tiltable jaw 3, astop-plate 4 and also several beams I7, 18 fixed to the baseplate bymeans of columns 21. Mounted on U-shaped beams are the bush holders 5,whose leg portions are provided at the free. ends with two opposednotches conformingly receiving the dovetail-shaped, split fasteningprojection 8 of a split clamping ring 7. Tightening a screw 10 closesthe clamping ring 7 about a drill bush 6. The bush is then brought intothe position required and fixed on the beams 17 and 18 by bolts 13 andI4 engaging the bight portion of each holder 5. The beams 17 and 18 eachpresent a row of threaded holes 20 and have throughout their length agroove 15 of angular cross section adapted conformingly to receive thehook-shaped head of each bolt 14 to permit the latter to be moved andfixed at any point so as to fix the bush in any position required. Thebeams I7 and 18 can be fixed to the baseplate l at various heights bymeans of interchangeable columns 21.

The two jaws 2 and 3 serve to fix the workpiece. Jaw 2 is fixed tobaseplate 1, and jaw 3 is tiltably arranged on stopplate 4. Fixed to therear of stop-pliate 4 is a stop-bar 23 against which rests the tiltablejaw 3, which is flexibly held by two bolts. Arranged in the uprightsection of jaw 3 are two springs 27 side by side, which keep the uprightsection in a slightly raised position. Stop-plate 4 serves for thecoarse setting on the base-plate. Baseplate 11 presents two rows ofthreaded holes, 9 disposed at regular intervals. Stop-plate 4 has twoslots 25 aligned with respective rows of holes 9 and permitting theplate to be fixed in any position according to workpiece 30. For finefixing, the horizontal section of jaw 3 presents a bolts 28 which can bescrewed into the threaded hole of stop-plate 4. Tightening the bolt 28tilts jaw 3 forwards, thus fixing and concurrently pulling down theworkpiece. Owing to the tilt, however, the work-fixing surface of jaw 3is not parallel to the opposite fixing surface. To remedy this, theformer surface is provided with a number of halfround grooves, intowhich, before fixing the work, are placed half-round bars 29 with theflat side against the workpiece. This arrangement ensures parallelism ofwork-fixing through automatic turning of the said bars.

SETTING THE DRILL BUSH To permit the drill bush 6 to be set to theposition required for the work, a coordinate sliding gauge has beendevised. This is shaped as a right angle and is provided like anordinary sliding gauge with graduations in both the ordinate and theabscissa directions and carries on each arm a slide 48, 49, either withor without vemier. Slide 48 serves as a stop for the ordinate at screw54 fixed to the end of beam 17. Screw 54 thus serves for the finesetting of the zero position of the sliding gauge. Slide 49 is providedunderneath: with an angle piece 50 connected with acone tip holder 51,which holds a cone tip 52 upright and resiliently by means of a spring53.

The coordinates are set as follows:

Required is a borehole whose center, measured from the stop side (baseline) in the drawing, has an ordinate of 42 mm. and an abscissa of 57mm. The procedure now is to set the particular coordinates, viz. 42 mm.by slide 48, 57 mm. by slide 49, and then to place on the cone tip 52the bush 6 held by bush holder 5, thus automatically centering the bush.The bush holder can then be screwed fast at a suitable point along thebeam, so that bush 6 is fixed exactly in the position given in thedrawing. Arranged below beam 1.7 and along it is a stopbar 55, whichserves together with jaw 2 as a stop for the workpiece and together withanglepiece 50 of slide 49 as a support for the coordinate sliding gaugein measuring position. The coordinate sliding gauge may also be composedof two commercial sliding gauges fitted together.

ADJUSTABLE ANGLE SCALE When shafts of various diameters are to beprovided with bores arranged radially and spaced at specific angles, theproblem of exact angular setting arises. To solve this problem, theinvention includes an adjustable angle scale dial, which can be broughtinto the position required by sliding it along a guide member accordingto the diameter of the shaft to be machined. As all such shafts,regardless of diameter, are fixed between stop-surface 61 of the bushand jaw 2, all their center axes lie in the angle-bisecting plane 63 ofstop-surface 62 of jaw 2 and stop-surface 61. Accordingly, a bar 65presenting a scale 66 along its length corresponding to the variousshaft diameters is arranged at the side of jaws 2 and at an angle of 45degrees to the baseplate and rigidly connected to the baseplate and beam18, in such a manner that the semicircular angle scale 60 can be movedthereon in such a way that its center comes to lie on the center axis ofthe shaft to be machined and can be fixed there by a screw.

A pointer 70 fixed to a cylindrical permanent magnet 69 or a prismaticpermanent magnet 68 can now be magnetically fixed to the side of theshaft or, with longer shafts, on the circumference thereof, so that,being radial to the shaft, it indicates on the scale the exact anglethrough which the shaft was turned or should be turned. With nonmagneticwork pieces, fixing can be effected by a mechanical, fork-shaped clamp,which need not be specified here.

SWITCI-IABLE BALL BEARING SYSTEM A problem in the drilling or boring ofheavy workpieces is that the drill tends to deviate from the center inthe bush. As is known, exact centering of the drill in the bush is verydifficult in the case of relatively small diameters. For this reason,the new device is supported on a switchable ball bearing system, so thatthe rolling of the ball bearing reduces the friction of the whole deviceand thus facilitates centering. After centering, the ball bearing can bedisengaged, so that the support plate 33 is lowered to the machine baseand seated fast again. The halls lie in inward tapering holes 35 insupport plate 33 in such a way that the'downthrust of intermediate plate32 pushes them in and down far enough for them to project below and actas a rolling system on the machine base.

The downthrust of intermediate plate 32 is effected by the wedge actionof two relatively displaceable elements which, for low friction, act inconjunction with balls interacting with two narrow strips 40 or a broadplate 41. The strips or the plate present several holes 42 whosediameter is slightly smaller than that of balls 34, for the purpose ofreceiving the latter. As the friction near the top of the balls is veryslight, the balls can be easily pushed out of the holes by displacingthe strips or the plate. Balls 34 are arranged as near along the edge ofbaseplate l as possible, for even support of the latter.

In FIG. 7, a shows the ball still in the hole of the strip, while bshows the ball as pushed out by displacement of the strips. Inaccordance with the holes in the strips or the plate, the intermediateplate 32 has as many, but deeper holes for receiving the balls 34. Afterdisplacement of the strips or the plate, all balls 34 are pushed down.Intermediate plate 32, which has received balls 34, is thrust downaccordingly. This process pushes all balls 35 under the intermediateplate slightly out of the support plate 33 for rolling engagement withthe nonillustrated machine base. Displacement ofthe strips or the plateis effected by swiveling a ball-handle 38, 39, which acts by aneccentric stud 37 in the bore of a lever 36 or in the bore of the saidplate 41. The coacting lever is pivotally mounted on a pin 36a fixed tobaseplate 1, and its two ends are movably connected with the said strips40, so that the two strips move in opposition to each other, while plate41 only moves in one direction, with the result that balls 34 are pushedout, as mentioned. The switching system can also be designed in such away that the intermediate plate 32 stays fixed or is entirelyeliminated, i.e. that balls 35 come in direct contact with baseplate 1.Support plate 33 is thinner than the ball and is held against thebaseplate by screw 44 and a spring not specified, so that the ballsproject slightly during centering, so that baseplate 1 can roll on themachine base directly by means of balls, 35. After centering, swivelingthe ball-handle 38, 39 causes the strips 40 to press balls 34 andsupport plate 33 down, so that the drilling and boring device is againseated fast on the machine base.

' ADDITION TO WORK FIXING ELEMENTS Fine fixing of the work, instead ofbeing effected by tilting the jaw 3, can be effected by the relativedisplacement of two wedge jaws, not specified, coacting with jaw 3, inthat the displacement of the wedge jaws, one lying on the other, iseffected by means of a lever or an eccentric, and as both jaws lie flatagainst each other with their whole surface, there is no danger of anycanting, although there is no lateral guidance, in particular forworkpieces requiring a broad-fixing surface. Of course, ordinary vicescan be used instead of the spindleless fine-fixing system.

The clamping ring 7 can also be made of spring steel, in

which case the opened dovetail-shaped projection can be brought intosuitable shape directly by bending the spring steel.

Beams 17, 18 are each provided below and along their full length with anangled groove 15 adapted to the hook-shaped head of bolt 14, to permitbush holders 5 to be fixed at any point.

I claim:

1. A drilling jig comprising, in combination:

a. a baseplate;

b. a plurality of holder members;

c. mounting means for releasably mounting said holder members on saidbaseplate in a plurality of positions relative to each other,

1. each of said holder members being substantially U- shaped and havinga bight portion adapted to be mounted on said base plate by saidmounting means and two elongated leg portions having respective freeends remote from said bight portion;

d. threaded means on each holder member connecting said leg portions formoving said free ends toward and away from each other; and

e. a circumferentially split-clamping ring adapted to receive a drillbush therein,

1. said ring having a split annular portion and a split, substantiallydovetail-shaped fastening portion, the two parts of the split fasteningportion being connected by the annular portion,

2. each of said free ends being formed with a recess opposite thecorresponding recess on the other free end of the holder member,

3. said recesses being arranged simultaneously to engage said parts ofsaid fastening portion in clamping engagement when said free ends aremoved toward each other by said threaded means.

2. A jig as set forth in claim 1, wherein said annular portion freelyprojects from said holder member when said fastening portion isclampingly engaged in said recesses, said annular portion being ofresilient material.

3. A jig as set forth in claim 1, wherein said recesses are notches insaid free ends transverse to the direction of elongation of therespective leg portions.

4. A jig as set forth in claim 1, further comprising positioning meansfor positioning each holder member, said positioning means including agauge having two elongated arms fixedly connected transversely to eachother, guide means for guiding movement of said gauge relative to saidbaseplate, two slides longitudinally movable on said arms respectively,cooperating abutment'means on said baseplate and on one of said slidesfor establishing the position of said gauge, and a conical elementmounted on the other slide for movement transversely to thecorresponding arm for coaxial engagement with a drill bush held by theholder member to be positioned.

formed with a longitudinal groove of angular cross section ex tendingsubstantially over the entire length of the beam member, said threadedmember having a hook-shaped head conformingly engageable with saidgroove.

